Bird Flu Doesn't Spread Easily to Humans, Scientists Say

THURSDAY, Dec. 5, 2013 (HealthDay News) -- The H7N9 bird flu virus does not yet have the ability to easily infect people, a new study indicates.
The findings contradict some previous research suggesting that H7N9 poses an imminent threat of causing a global pandemic.
The H7N9 virus killed several dozen people in China earlier this year. Analyses of virus samples from that outbreak suggest that H7N9 is still mainly adapted for infecting birds, not people, according to scientists at the Scripps Research Institute in La Jolla, Calif.
The study is published in the Dec. 6 issue of the journal Science.
"Luckily, H7N9 viruses just don't yet seem well adapted for binding to human receptors," Ian Wilson, a professor of structural biology and chair of the department of integrative structural and computational biology, said in a Scripps news release.
"Because publications to date have implied that H7N9 has adapted to human receptors, we felt we should make a clear statement about this," James Paulson, chair of the department of cell and molecular biology, said in the news release.
H7N9 flu viruses infect birds, causing few or no symptoms. Until this year, H7N9 strains had never been reported in humans. But in February, dozens of people in two urban areas of eastern China began to come down with H7N9 flu, and most of them became severely ill.
When the outbreak was mostly over by the end of May, there were 132 human cases confirmed by a laboratory and 37 deaths -- a death rate of nearly 30 percent.
Public health officials were alarmed by the outbreak and there were concerns that H7N9 might trigger a global pandemic.
"These results suggest that we should continue to observe H7N9 and see if it undergoes any changes that make it more likely to spread in the human population," Wilson said.